Tapping spindle with torque release clutch built into its shank and having automatic depth control

ABSTRACT

A tapping spindle having a shank with a torque release clutch built into the shank so that the overall size is reduced adapting it for use in a machine carrying multiple closely spaced spindles. The clutch comprises a driving sleeve and a driven sleeve member, and is combined with an automatic depth control in the spindle. In one form the tapping spindle has a removable tool chuck holder having the torque release chuck built into it, the holder being rotatable relative to the spindle.

United States Patent 1 Johnson 1 1 TAPPING SPINDLE WITH TORQUE RELEASECLUTCH BUILT INTO ITS SHANK AND HAVING AUTOMATIC DEPTH CONTROL [75]Inventor: Allan S. Johnson, Newport Beach,

Calif.

[73] Assignee: Tapmatic Corporation, Costa Mesa,

Calif. I

[22] Filed: Mar. 15, 1971 [2]] Appl. No; 124,020

[52] US. Cl 408/139, 408/14, 408/142, 408/239, 279/79, 279/97 [51 1 Int.Cl. B23b 47/24, B23b 31/04 [58] Field of Search 408/239, 238, 5, 139,141, 408/142; 10/134, 135 R; 279/1 B, 97, 79,14,

[56] References Cited UNITED STATES PATENTS Scholtes 10/135 R X 1 1 Feb.12, 1974 2,527,517 10/1950 Barker et a1. 10/135 R X 2,764,416 9/1956Martin 408/139 X 2,540,937 2/1951 Edens 279/79 2,773,693 12/1956Chittenden 279/97 X 2,206,047 7/1940 Poorman 408/139 3,002,206 10/1961Johnson 408/139 Primary ExaminerGil Weidenfeld Attorney, Agent, orFirmHerzig & Walsh [57] ABSTRACT A tapping spindle having a shank with atorque release clutch built into the shank so that the overall size isreduced adapting it for use in a machine carrying multiple closelyspaced spindles. The clutch comprises a driving sleeve and a drivensleeve member, and is combined with an automatic depth control in thespindle. In one form the tapping spindle has a removable tool chuckholder having the torque release chuck built into it, the holder beingrotatable relative to the spindle. I

2 Claims, 13 Drawing Figures Pmmw cm 3,791,756

SHEET 2 BF 3 INVENTOR. 4114/1/ 5. ./0///V50A/ PATENTED "B 21974 sum 3 0F3 -INVENTOR 411 EA/ 5 JOA A/SO/V TAPPING SPINDLE WITH TORQUE RELEASECLUTCH BUILT INTO ITS SIIANK AND HAVING AUTOMATIC DEPTH CONTROL SUMMARYOF THE INVENTION The invention is a tapping spindle, particularlyadapted for use in machines having a head carrying multiple spindlessuch as for example, 20 spindles, all individually driven. With thistype of machine, it is possible to drill or tap multiple holes in a workpiece at the same time. It may be desirable to tap holes of differentdepths so that different spindles areadjusted to extend differentamounts from the head. The spindle of the invention embodies an improvedtorque release clutch which is of small diameter and which is built intothe spindle itself, thereby making it possible to have spindles closertogether and to have more of them carried by the same head, for drillingor tapping multiple holes simultaneously.

. Embodied in the spindle in combination with the improved clutch is anautomatic depth control which causes the spindle to automaticalydeclutch at the proper depth.

A preferred exemplary form of the invention is described in detailherein. Further specific improvements are included in the detaileddescription.

The primay object of the invention is to provide an improved spindle ofa reduced diameter wherein a torque release clutch is embodied withinthe spindle itself combined with depth control means adapted to declutchat a desired predetermined depth.

A further object is to provide an improved torque release clutch ofreduced diameter embodying a sleeve having a skirt cooperable with drivepins and with a drive pin for driving the sleeve cooperating with a slotin the sleeve whereby to hold the sleeve out of driving position uponrelease of the clutch.

A further object is to provide a torque release clutch as in theforegoing built into the shank of a tapping spindle and combined with adepth control mechanism in the shank.

A further object resides in the provision of an improved quick changecollet chuck, embodying a replaceable hex jaw whereby hex jaws may beprovided in sets having different size square holes adapted fordifferent sizes of tapping tools making it unnecessary to have differentsizes of collect chucks and nuts.

A further object is to provide an improved tapping spindle having aquick change chuck assembly with the torque release clutch built intothe quick change assembly so that when a change is made for differenttools, the setting of the torque release clutch clutch can be changedwithout removing the tool from the machine.

BRIEF DESCRIPTION OF THE DRAWINGS Further objects and additionaladvantages of the invention will become apparent from the followingdetailed description and annexed drawings wherein:

FIG. 1 is a schematic view illustrating an installation of one of thetapping spindles of the invention;

FIG. 2 is a cross sectional view of a preferred form of the tappingspindle of the invention;

FIG. 3 is a cross sectional view taken along the line 3-3 of FIG. 2;

FIGA is a cross sectional view taken along the line 4-4 of FIG. 2; v

FIG. 5 is a cross sectional view taken along the line 5-5 of FIG. 2;

FIG. 6 is a cross sectional view taken along the line 6-6 of FIG. 2;

FIG. 7 is a perspective view of the combined torque release clutch andautomatic depth control mechanrsm;

FIG. 8 is a perspective view showing the torque release clutch in asecond position; and

FIG. 9 is an exploded view of the quick change chuck or tool holderembodied in the spindle.

FIG. 10 is a cross sectional view of a modified form of tapping spindle.

FIG. 11 is a cross sectional view taken along line 11-11 of FIG. 10.

FIG. 12 is a cross sectional view taken along line 12-12 of FIG. 10.

FIG. 13 is a perspective view of the-torque release clutch of FIG. 10.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now in more detail tothe various figures of the drawings, numeral 10 designates a head of amachine adapted to carry multiple, closely spaced spindles, each one ofwhich is individually gear driven. Nu-

meral 12 designates schematically the improved spindle of the invention,difi'erent parts of which will be described in detail in connection withthe various figures herein.

Head 10 has rotatable stems forming receptacles to receive the shanks ofindividual tapping spindles which are secured in the receptacles indesired positions. In

FIG. 2, numeral 14 designates a stem which is within the head 10 andwhich is driven and which forms a receptacle to receive the spindle 12.The spindle has the cylindrical shank member 20, the upper part of whichis received in the bore 22 of the cylindrical stem 14. The shank member20 has a milled tapered flat 24, and it is held in position by a setscrew 26 which engages against the flat, and by which the amount ofinsertion is fixed.

Numeral 30 designates a Woodruff key which is fitted into an opening inthe opposite side of the shank member 20 and which moves in an axialgroove 32 on the inside of the tubular stem 14.

The lower part of the member 20 is threaded as shown. Numeral 34designates a threaded collar which fits onto the threaded part of themember and which engages against the lower end of the tubular stem 14.It may be set in position by way of set screw 36, engaging shoe 37.

The Torque Release Clutch The torque release clutch is of relativelysmall diameter and it is built into the shank 20 of the spindleassembly. It is shown in detail in the upper part of FIG. 2, in thecross sectional views FIGS. 3 and 4, and in FIGS. 7 and 8.

The torque release clutch is an improvement on the torque release clutchof US. Pat. No. 3,472,347. It embodies a tubular member or sleeve 40which fits within bore 42 within the shank member 20. At an intermediatepart of the sleeve member 40, there is a transverse septum or partition44 having a centralbore through which extends the cylindrical stem 46having a head 48 and at the lower end of which there is a lug 50 towhich is secured suspension spring 52. The spindle of the invention isof a type having free axial float as described in previous patents suchas the one referred to above and also US. Pat. No. 3,397,588.

The lower end of sleeve 40 is formed to have a group or plurality of cutouts as may be seen in FIGS. 7 and 8, the cut outs having one axial sideas designated at 60 and a slanting or angular side as designated at 62.Numeral 64 designates a driven sleeve member which is the depth controlmember, the upper cylincrical part of which is designated at 66 andwhich is within the skirt at the lower part of the sleeve 40. In thepart 66, there are three radial bores 67a, 67b, and 670 in which areradial pins 68a, 68b and 680 which are received in the group of cut outsin the lower end or skirt of the sleeve 40 as previously described inconnection with FIG. 7. The member 64 is driven by the sleeve member 40as will be observed by way of the pins 68a, 68b, and

680, engaging in the cut outs. The slanting surface 62 of sleeve 40engages pins such as 68a as may be seen in FIG. 7 to drive part 64. Thetorque tends to force the sleeve 40 upwardly.

In the side wall of the upper part of the sleeve 40 is a right angleslot 70 having an axial part 71 and a circumferentially extending part73. Numeral 75 designates a radial pin fitted in a bore in a side wallof the upper part of the shank and this pin engages in the right angleslot 70 for a purpose which will be described presently.

Numeral 72 designates a coil spring, the lower end of which fits withinthe upper part of sleeve 40 against the partition or septum 44.'Theupper end of spring 72 engages disc 74 of a thrust bearing whichembodies a second disc 76 carrying angularly spaced balls 78 that rideagainst the disc 74. The upper end of the member 20 is internallythreaded, as designated at 82 and received within the threaded bore isan end cap 84 having a center opening 86 adapted to receive a wrench foradjusting the end cap to thereby adjust the force exerted by spring 72against the thrust bearing. The torque release clutch is of courseresponsive to the amount of driving torque and the predetermined torqueat which the clutch will release is determined by the setting of the endcap member 84 which determines the bias of the spring 72 and thus theamount of pressure exerted on the sleeve 40 which will cause it to moveup and disengage from the pins 68, as described more in detailhereinafter.

The operation of thetorque release clutch will be readily understoodfrom the foregoing. At a predetermined torque determined by the settingof the bias spring 72, the force exerted by the slanting surfaces 62causes the sleeve 40 to, move upwardly against the spring 72 anddisengage from the pins 68. Such position of sleeve 40 is illustrated inFIG. 8, in which position the pin 75 has moved from the axial part ofthe right angle slot 71 into the circumferential part 73 as shown; andin this position, it holds the sleeve 40 lifted as shown in FIG. 8 inwhich position the drive has been released and no torque is transmitted.In the event of reversal of rotation of the direction of the drive, thesleeve 40 will be rotated in a direction opposite to the direction ofthe arrow of FIG. 8 which will cause the radial pin 75 to be movedrelatively to the axial part 71 I of the right angle slot, allowing thesleeve 20 to drop down so that the pins 68 again move into the cut outsand into engagement with the axial edges or surfaces 60 of the cut outsto provide for positive reverse drive.

When the clutch releases sleeve 40 moves angularly; the thrust bearingallows the end of spring 72 to freely rotate without twisting.

The torque release clutch is of simplified form and is of small diameterand is built into the shank of the spindle to thereby reduce itsdiameter. As previously pointed out, the torque release clutch whichwill release at a predetermined torque is combined with an automaticdepth control.

Automatic Depth Control The automatic depth control embodies the drivensleeve member 64 already referred to. Upper part 66 has a bore 92 inwhich is a bushing 94 through which the stem 46 extends, there being acoil spring 96 around the stem 46 between the upper end of the drivenmember 64 and the septum 44. The driven member 64 releases upon anupward axial movement against the force of spring 96 as will bedescribed. At the lower end of member 64 it has a skirt part 100 havingan axial slot 102 as shown in FIG. 7. Referring to the slot 102 shown inFIG. 7, it has a straight side 104 and another side 106 at the lower endof which is rounded or contoured off as shown at 108. Numeral 114designates the driven spindle at the upper part of which is a bore 116having in it a bushing 118, spring 52 passing through this bushing. Atthe upper end of the spindle stern 114 there arethree radial bores 120a,120b, and 1200 in which are radial pins 122a, 122b, and 1226 which arereceived in the axial slots like the slot 102 of FIG. 7. See FIG. 5.

From the foregoing, the operation of the automatic depth control will bereadily understood. As tapping progresses, the pins 122 will movedownwardly in the vertical slots 102. When they reach the curved or con-Quick Change Chuck and Driven Spindle Stem The spindle stem 114 has amain bore 130, the bore 116 being a counterbore. These two bores areconnected by a taper as shown. The spindle stern 114 is journalled in abushing 132 which is inthe lower end part of the cylindrical shank 20and it may be set in position by way of a set screw 134. The lower endof the spindle stem 114 is enlarged as designated at 138, this partbeing externally threaded as shown and there being a threaded capengaged on it, the cap having a bore 142 through which the stern 114extends. N umeral 144 designates a set screw whereby the position of thecap 140 can be fixed. Numeral 139 designates a relatively heavy springbetween bushing 132 and part 138. In a multiple spindle machine if a bitshould come down on a work piece where no hole had been drilled, nobreakage would occur since the tool holder can push up against thisspring. The part 138 has a bore with a smaller counterbore 152. Fittingin the counterbore 152 is a bearing 154 within in which is a short stem156 having a head 158'and a lug 160 to which is attached the lower endof the spring 52.

Numeral 168 designates the quick change chuck assembly which is shown inmore detail in FIGS. 6 and 9. The quick change assembly comprises asleeve memher 170 which fits into the bore 150 in the part 138. Sleeve170 has a transverse partition or septum 172 as shown. It has anintermediate flange 174 and an enlarged threaded boss 176 at its lowerend. At its upper end, it has a bore 180. It also has bores 182 and 184of the same diameter with a bore 186 in between these two of slightlysmaller diameter and it has tapered end bore 190.

In the upper end of sleeve 170 in the sides thereof are formed arcuategrooves or cut outs as designated at 181 and 183. See FIGS. 6 and 9.Numeral 185 designates a transverse pin that is received in these cutouts and the ends of which are received in diametrically opposite radialbores in the part 138 as designated at 186 and 187. The part 138 of thespindle stern drives the quick change chuck assembly by way of the pinor shaft 185 and the cut outs 186 and 187. As will be observed, thesecut outs extend through an angle of more than 180 degrees so that theentrance to these cut outs subtends an angle of less than 180 degrees.When torque is being applied, the ends of the shaft or stem 185 moveagainst a side of each of the cut outs and then the extending lip orshoulder at the entrance to the cut out prevents axial pull-out of thepin or shaft 185 and thus prevents the quick change chuck assembly frombeing pulled out while being driven, the neophrene ring 186 having onlyenough holding force to hold the quick change assembly in position whennot loaded, as will be described.

At the lower end of part 138 on opposite sides, there is an arcuateannular groove as shown at 192 and there are four equal spaced radialbores 194a, b, c, and d which intersect with the bore 150. Numeral 196designates a flexible neoprene ring which fits around the lower end ofpart 138 and into the arcuate groove 192 to engage against steel balls198a, b, c, and d in the radialbore whereby to urge them inwardly intoannular groove 197 in the wall of the sleeve part 170 to hold the quickchange assembly in position.

Numeral 200 designates a hex jaw, the upper part of which is hexagonalbeing broached into the bore 182, the lower part of which fits into thebore 186 of smaller diameter. the hex jaw has a square center hole 201to receive the square end 206 of a tool as designated at 208 in FIG. 9.The hex jaw 200 is itself replaceable, there being a set of these hexjaws each having a different size square hole adapting it to taps ofdifferent sizes. Thus, for different size taps, only this hex jaw needbe replaced rather than replacing the complete collet assembly. Sincethe hex jaws are interchange able, the chucks may be of the same size,the only difference in the hex jaws being the different size squareholes in them.

The chuck assembly may otherwise be conventional and may be like thatshown in U.S. Pat. No. 3,472,347. A plurality of tapered collet jaws 212are positioned within the tapered bore 190 and are held in upwardposition by threaded collet cap 214 which threads on to the boss 176 andhaving a bore 216 through which the tool 208 passes, Numeral 218designates a washer that engages against the collet jaws 212.

SUMMARY OF OPERATION From the foregoing description of the componentparts, those skilled in the art will readily understand the overalloperation. The toolis set in the collet as described, and the quickchange assembly is fitted into the end part 138 of the driven spindle.The threaded cap 140 may be set in a desired position and screw 144 setup. An adjustment of the cap 84 adjusts the tension at which the clutchwill release as described in the foregoing. The depth control willrelease at the desired depth control setting. This is determined by thesetting of the shank 20 within the stem 14 as described.

Modifications of FIGS. 10 through 13 FIGS. 10 through 13 of the drawingsillustrate a modified form of the invention embodying certain additionalimprovements. One of these is that the torque release clutch is builtinto the quick change chuck assembly to realize advantages as alreadyset forth. The collet check is part of a fitting that carries the hexjaw and this fitting itself is relatively rotatable with respect to thequick change chuck assembly for reasons which will be made clear. Theretaining feature for holding the quick change chuck assembly inposition under load is slightly modified, as will be explained.

Those parts of the modification of FIGS. 10 through 13 which correspondclosely to similar parts of the previous embodiment are identified bythe same reference characters primed; and tothe extent that thedescription of the previous embodiment applies to this one, thedescription will not be repeated.

As may be observed, in FIG. 10, the torque release clutch is at thelower part of the figure within the quick change chuck assembly. Thedepth control mechanism is very similar to that of the previousembodiment. The shank 20' is guided in the stem 14 by the arcuate piece30 which fits into a recess on the side of the shank 25 and moves inaxial slot 32. Fitting in the upper end of the shank 25 is a plug 220having a depending skirt 222 and an extending boss 224. It has a bore225 and a counter bore 226. As may be seen, the stem 46' extends throughthe end fitting or plug 220 through the bushing in the upper part of thedriven sleeve 64' and through the upper part of the driven spindlemember 1 14', this spindle stem being similar to that of the previousembodiment; but because of its length, greater assurance ofconcentricity is provided. The skirt 222 has a side cut-out 230 in whichthe radial pin engages. Numeral 232 designates a biasing spring biasingthe upper end of the driven sleeve 64' and the end fitting 220 and theboss 224 serving as a spring retainer.

The depth control mechanism operates like that of the previousembodiment, and it is not necessary to describe this operation again. Itmay be pointed out, however, that on release at the set depth, drivensleeve 64' moves upwardly against the spring 232 with the pin 75 movingin the slot or cut-out 230.

The lower end of the spindle stem 114 is enlarged and cup-shaped asdesignated at 240, having a bore 242, counter bore 244, in addition tothe counter bore 152 that receives the bearing 154 like the onepreviously described. The spindle stem 114 is threaded as designated at246 and threaded to it is an internally threaded disc 250 which may beset in position by a set screw 252. Disc 250 may be adjusted against thetension of spring 139 and the effect of which is to adjust the point ofautomatic depth control release.

The quick-change chuck assembly is designated generally at 260. Itcomprises the sleeve 262, the upper parts of which as designated at 263and 264 fit into the counter-bores 244 and 242 respectively in the part240. The sleeve 262 has a bore 268 and a threaded counter-bore 270. Thetorque release clutch is built in to the sleeve member 262 which isremovable in a manner similar to that of the previous embodiment notrequiring further description. The parts of the torque release clutchare shown in FIG. 13. These parts comprise a sleeve 274 having a bore276 which fits into the bore 268 in the sleeve 262. The sleeve 274 hastwo diametrically opposed cut-outs, one of which is designated at 277,having an axial part 278 and circumferential part 279, this cut-outcorresponding to the cut-out 70 of the previous embodiment. Pin 280extends diametrically so that its end parts can be received in thecutouts. Numeral 281 designates a coil spring that fits inside of thesleeve 274 which has a bottom 281 and the other end of the springbearing against threaded ring 284 which threads into the threadedcounter-bore 270 in the upper end of the sleeve 262. This ring hassquare center opening 287 adapted to receive a wrench for adjustment toadjust the tension on the spring 281 to thereby adjust the magnitude ofthe torque at which the torque-release clutch will release.

At the lower end of the clutch sleeve 274 there are three extending lugsas shown at 292 in FIG. 13, each having one axial surface as designatedat 293 and a beveled surface as designated at 294, with angularly spacedgaps in between the lugs.

Numeral 300 designates generally a sleeve or fitting which forms thecollet chuck holder and which is relatively rotatable with respect tothe sleeve 262 and which carries the mating parts of the clutch. Thelower part of the holder 300 is like that of the previous embodiment. Ithas an intermediate flange 302 and an upper part 303 which is receivedin the bore 268 and this part has three extending lugs, one of which isdesignated at 304 in FIG. 13, each having one axial surface 306 andbeveled surface 308 like the corresponding surfaces on the lugs of theclutch sleeve 274. These lugs are similarly oppositely configurated withsimilar angularly spaced gapsin between them.

'The lower end of the bore 268 in the sleeve 262 has an annular grooveof semi-circular cross-section in it as designated at 314 and the upperpart of the holder 300 has a similar groove 316 in it, so that aring-shaped opening is formed which is normally filled or loaded withball bearings as designated at 318, which may be loaded in through aradial bore 320, which is then closed with screw 322. Thus, these ballsprovide a bearing enabling the chuck holder to freely rotate withrespect to the assembly 260.

The torque release clutch shown in FIG. 13 operates similarly to thetorque release clutch of the previous embodiment. At a predetermined settorque the action of the beveled surfaces of the lugs on the clutchsleeve 274 and on the holder 300 will cause the clutch sleeve 274 tomove axially against the force of spring 281 to cause the diametricalpin 280 to move down into the circumferential parts 279 of the cut-outsin clutch sleeve 274 and thus to hold the clutch sleeve in an upwarddisengaged position until the direction of rotation is reversed, atwhich time the clutch will reengage for operation in the reversedirection.

The quick-change assembly is held into the part 240 in a manner similarto that of the previous embodiment. In this form also when the tappingspindle is under load,

the torque acts to prevent the quick-change assembly from coming out. Inthe .upper part 263 of the sleeve 262 there are diametrically opposedrecesses or cutouts as may be seen at 330 and 330a in FIG. 12. Theserecesses or cut-outs are configurated like the cut-outs 181 and 183 ofthe previous embodiment so that the openings into them is less thantheir diameter or width so that a lip is formed at the side of theentrance opening to the cut-outs.

Numerals 332 and 332a designate radial pins received in diametricallyopposite radial bores 334 and 334a in the part 240, the ends of thesestems engaging in the cut-outs 330 and 330a. Thus, it may be seen thatwhen the tapping spindle is under load the torque causes the pins 332and 332a to be forced against the sides of the cut-outs in which theyengage, so that the lips at the entrances to the cut-outs overhand thepins and prevent the quick-change assembly from pulling out.

The collet chuck itself is like that of the previous embodiment.However, in the neck 214 an additional counter-bore 340 is provided andin the bore 216 and the counter-bore 340 there is provided a washer orring member 342 having a flange received in the counter-bore 340.

The operation of the components of the embodiment of FIGS. 10-13 hasbeen described in connection with the description of their constructionand will be readily understood, particularly in the light of thedescription of operation of the previous embodiment. The additionaladvantages of this embodiment will be readily apparent to those skilledin the art and as summarized in the foregoing. The tool need not beremoved from the machine in order to change the setting of the torquerelease clutch which is removed with the quick-change assembly. In thisassembly the hex jaw construction is like that of the previousembodiment. The position of automatic depth control release is similarlyset.

From the foregoing those skilled in the art will fully understand thenature and construction of the invention and the manner in which itachieves and realizes all of the objectives and advantages as setforth'in the foregoing.

The foregoing disclosure is representative of ap referred form of theinvention and is to be interpreted in an illustrative rather than in alimiting sense, the invention to be accorded the full .scope of theclaims appended hereto.

What is claimed is:

1. A tapping spindle having a shank part adapted to be received in amachine, said tapping spindle having a stem with a receptacle at one endfor carrying a modular tool holder assembly, said assembly including atool holder, releasable means for holding the tool holder assembly inthe receptacle and constructed to hold the assembly by friction forquick removal and for quick change of the tool holder, the modular toolholder having a torque release clutch built into it with means foradjusting the magnitude of the torque at which the clutch will releaseso that the release torque can be adjusted whenever the modular toolholder assembly is removed.

2. A tapping spindle as in claim 1 wherein said tool holder assemblycomprises a body part adapted to be received in the receptacle and arelatively rotatable sleeve part carried by the body part, and a colletchuck for holding a tool carried by the sleeve part.

1. A tapping spindle having a shank part adapted to be received in amachine, said tapping spindle having a stem with a receptacle at one endfor carrying a modular tool holder assembly, said assembly including atool holder, releasable means for holding the tool holder assembly inthe receptacle and constructed to hold the assembly by friction forquick removal and for quick change of the tool holder, the modular toolholder having a torque release clutch built into it with means foradjusting the magnitude of the torque at which the clutch will releaseso that the release torque can be adjusted whenever the modular toolholder assembly is removed.
 2. A tapping spindle as in claim 1 whereinsaid tool holder assembly comprises a body part adapted to be receivedin the receptacle and a relatively rotatable sleeve Part carried by thebody part, and a collet chuck for holding a tool carried by the sleevepart.